The Texas Instruments LM1085IS-ADJ/NOPB is a single-output adjustable positive LDO regulator rated for 3 A continuous output. It comes in a DDPAK/TO-263-3 surface-mount package.
Dropout and headroom — what 1.5 V at 3 A means
The maximum dropout voltage of 1.5 V at 3 A sets the minimum input-to-output differential needed to maintain regulation.
75 dB PSRR at 120 Hz — ripple rejection in post-regulation
The 75 dB PSRR at 120 Hz attenuates line-frequency ripple.
Temperature grade and environment
Rated for a junction temperature range of -40°C to 125°C, the LM1085IS-ADJ/NOPB is qualified for industrial environments: motor drives, outdoor telecom cabinets, factory automation panels, and under-hood automotive auxiliary supplies. The junction temperature, not ambient, is the binding limit — 3 A at high input-output differential generates significant self-heating, so the DDPAK tab must be soldered to a sufficient copper plane for thermal dissipation.
Protection features
Over-current and over-temperature protection are built in. The regulator folds back current during a fault and shuts down if the die exceeds the thermal limit. No external protection diode or current-limit resistor is needed for normal operation, though the output capacitor should be rated for the full input voltage in case of a short-circuit condition.
Lifecycle and sourcing
The LM1085IS-ADJ/NOPB has an active lifecycle status per the manufacturer. No last-time-buy or end-of-life notice is in effect. The part is RoHS3 compliant (lead-free).